Authorities in Pakistan have arrested several people in connection with a school massacre last week in which nearly 150 students and teachers were killed.

Interior Minister Chaudhry Nisar Ali Khan alleges those detained were "facilitators" of the brutal, hours-long assault on the military-run school in the northwest city of Peshawar.

He did not release the number of arrestees or details about their identities.

Taliban gunmen wearing explosives infiltrated the facility on December 16, shooting indiscriminately at children and staff.

Khan also said the government has information that terrorists may be planning a second similar attack.

Khan gave no details of the information, but said the entire country has to stay alert. He warned mobile telephone companies that they could face terrorism charges if they issue illegal phone identification cards.

Khan also said hotel owners must check on their guests' credentials and will be held responsible if they rent rooms to a terrorist. He urged all Pakistanis to share any information they have with security agents.

On Sunday, Pakistan executed four Islamist militants after lifting a six-year moratorium on the death penalty in reaction to the school massacre.

The four convicts were hanged at a prison the eastern city of Faisalabad for their role in a plot to assassinate former Pakistani president Pervez Musharraf. Two others convicted in the plot were hanged Friday.

Human rights groups have condemned Pakistan's decision to reinstate executions, saying it will not stop terrorism and may even feed a “cycle of revenge."